Method for cooling electronic components in an aircraft turbojet engine

ABSTRACT

A method for cooling electronic components present in an aircraft turbojet engine, the method including disposing a first sensor in a first zone of the turbojet engine; disposing a second sensor in a second zone of the turbojet engine, the first zone and the second zone having a temperature gradient between them; generating, from the first sensor and the second sensor, electricity by the Seebeck effect; bringing about cooling of the electronic components by the Peltier effect, using the electricity generated by the Seebeck effect.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to French Patent Application No. 1251219 filed Feb. 9, 2012. The content of this application is incorporated herein by reference in its entirety.

FIELD

The invention relates to a method for cooling electronic components in an aircraft turbojet engine. The technical area of the invention is, in a general manner, that of aircraft engines, and more particularly that of the protection of the electronic components present in such engines.

BACKGROUND

Electronics boxes present in the turbojet engines of aircraft are for example elements which link a control computer and an overspeed protection system, the functioning whereof is as follows: the purpose of the control computer is to regulate the speed of the turbojet engine; a malfunction of the control computer can give rise to overspeed. This is why it is necessary also to install an overspeed protection system in such boxes. The overspeed protection system thus typically comprises an electronic element associated with a hydromechanical element. The electronic element measures the rotational speed of the rotor. If the electronic element detects an overspeed, it then commands the hydromechanical element which cuts the fuel.

The strategic nature of these electronics boxes is thus well understood, as is the need to preserve their optimum functioning. Also, in order to guarantee ideal functioning of such boxes, it is essential to ensure suitable cooling of these electronic boxes, whatever the operating conditions of the turbojet engine to which they belong.

New difficulties are gradually appearing in respect of the use of methods of cooling electronics boxes inside turbojet engines, these new difficulties being associated with the modification of the structure of some turbojet engines, and/or the requirements of customers.

Thus, for example, a problem of available space for providing the cooling of the electronics boxes arises in the fan compartment of some turbojet engines. This emerging problem follows an increase in the diameter of the fan in a limited overall turbojet engine volume, the height under the cowl now being reduced for putting cooling systems into place.

Next, new demands in terms of performance are arising, these demands requiring the introduction of ventilation and cooling systems which are virtually transparent in terms of fuel consumption.

Some solutions have already been proposed in this context for the provision of ventilation and cooling of electronics boxes, particularly when the aircraft in question is stationary on the ground.

A first solution comprises a ventilation system with internal intake upstream of the fan and an external boom online outlet on fans of the “fan cowl” type. Such a system makes use of pressure differences to circulate the air from the exterior to the interior when the aircraft is stationary, then from the exterior to the interior when the aircraft is in motion. But this system is complicated to install, takes up considerable space and has a not inconsiderable mass. Moreover, it consumes air continuously, which obviously has an unfavourable impact on the aerodynamic performance of the turbojet engine.

The second envisaged solution comprises a ventilation system with an inlet and an outlet externally connected to an eductor to provide ventilation when the aircraft is stationary. These systems are complex, heavy and excessively noisy.

A third solution comprises a ventilation system using an electric fan. Here again, the system is complicated to install, takes up considerable space and has a not inconsiderable mass.

The existing solutions thus present all the major drawbacks. In future, the ventilation problems of electronics boxes will inevitably become increasingly significant, because the engines in which they are installed are becoming increasingly compact and the electronics boxes are generating more and more power.

SUMMARY

An aspect of the invention essentially relates to a method for cooling the computers of turbojet engines, but it can also be used for any electronics box present in the turbojet engines of aircraft.

An aspect of the invention offers a solution to the problems which have just been discussed, by proposing a method of cooling electronic components present inside a turbojet engine, said method not being complicated to install, or bulky or heavy, but using the permanent presence of temperature gradients in the engines in question. In this regard, the method according to an embodiment of the invention proposes successive use of two thermoelectric effects known under the names “Peltier effect” and “Seebeck effect”.

It is recalled here that the Peltier effect is a physical phenomenon of heat displacement in the presence of an electric current. It is currently used for iceboxes or refrigeration systems in the space or military fields, where precision and reliability are required. The Peltier effect is produced in conductive materials of different kinds linked by junctions or contacts.

It is recalled, moreover, that the Seebeck effect is a thermoelectric effect opposite to the Peltier effect. The Seebeck effect is a phenomenon according to which a temperature difference gives rise to an electric potential difference. This effect is therefore based on the generation of electricity by thermoelectric effect.

In an aspect of the invention, therefore, it is proposed to use thermal gradients naturally present in the engines to generate electricity by the Seebeck effect, then to use this electricity to refrigerate electronic boxes by the Peltier effect.

An embodiment of the invention thus essentially relates to a method of cooling electronic components present in an aircraft turbojet engine, the method comprising:

-   -   disposing a first sensor in a first zone of the turbojet engine;     -   disposing a second sensor in a second zone of the turbojet         engine, the first zone and the second zone having a temperature         gradient between them;     -   generating, from the first sensor and the second sensor,         electricity by the Seebeck effect;     -   bringing about cooling of the electronic components by the         Peltier effect, using the electricity generated by the Seebeck         effect.

Apart from the main features which have just been mentioned in the preceding paragraph, the method according to an embodiment of the invention can comprise one or more additional features among the following, considered individually or according to the technically possible combinations:

-   -   the method comprises the additional step consisting in storing         electrical energy, generated by the Seebeck effect, in a module         capable of storing electrical energy, the electrical energy thus         stored then being used to bring about the cooling of the         electronic components by the Peltier effect.     -   the temperature gradient between the first zone and the second         zone of the turbojet engine is an axial temperature gradient.     -   the first zone is a zone comprising a turbine of the turbojet         engine, and the second zone is a zone comprising a compressor of         the turbojet engine.     -   the temperature gradient present between the first zone and the         second zone of the turbojet engine is a vertical temperature         gradient.

Embodiments of the invention and its various applications will be better understood upon a reading of the following description and upon examination of the FIGURE accompanying the latter.

BRIEF DESCRIPTION OF THE FIGURE

The single FIGURE is presented solely by way of indication and under no circumstances limits the invention.

It shows a symbolic representation of a turbojet engine equipped with electronic components, in respect of which the method according to an embodiment of the invention is used.

DETAILED DESCRIPTION

FIG. 1 shows a diagrammatic representation of a turbojet engine 101 which comprises successively, in a simplified manner, a compressor 102, a compression chamber 103, in which the circulating air is increased in temperature when turbojet engine 101 is in operation, and a turbine 104. Turbojet engine 101 is also equipped with a box 110, for example of the FADEC box type, comprising an assembly of electronic components to be cooled.

Once it has been put into operation, the turbojet engine systemically comprises first zones 105 having a temperature much higher than those of second zones 106, essentially on account of the heating of the air flow circulating in turbojet engine 101; the coexistence of hot zones 105 and cold zones 106 thus creates an axial temperature gradient, i.e. a temperature gradient orientated in the direction of circulation of the air inside turbojet engine 101.

In an embodiment of the invention, it is proposed to take advantage of the natural existence of this temperature gradient in order, by means of the Seebeck effect and thanks to the presence of a first sensor 107 disposed in hot zones 105 and a second sensor 108 disposed in cold zones 106, to generate electricity inside a module 109 capable of storing electrical energy. The electricity thus generated is then used to cool, by the Peltier effect, box 110 containing electronic components. Module 109 is connected by electrically conductive wires 111 to sensors 107 and 108. Moreover, module 109 is connected by electrically conductive wires to cells 113, so-called Peltier cells, capable of cooling box 110.

In an embodiment of the invention, it is also proposed to take advantage of the existence of a vertical temperature gradient, which arises as soon as the turbojet engine has been put into operation, but which also continues when it is stopped; the use of suitably positioned sensors once again makes it possible to take advantage of the natural existence of this temperature gradient in order, by the Seebeck effect, to generate electricity inside module 109 capable of storing electrical energy. The electricity thus generated is also used to cool, by the Peltier effect, box 110 containing electronic components.

The method according to an embodiment of the invention is thus used without any intake of air to cool the electronic components, which makes it possible to avoid adversely affecting the aerodynamic performance of the turbojet engine. Moreover, it can also function even when the aircraft is stopped, because the described temperature gradients continue to be present for some time; finally it can be utilised by making use of vertical temperature gradients, when the engine is stopped.

The simultaneous use of the Peltier and Seebeck effects thus makes it possible to succeed in using an independent method, which requires neither external ventilation, nor any energy contribution other than that provided by the existence of the temperature gradient. 

1. A method for cooling an electronic component in an aircraft turbojet engine, the method comprising: disposing a first sensor in a first zone of the turbojet engine; disposing a second sensor in a second zone of the turbojet engine, the first zone and the second zone having a temperature gradient between them; generating, from the first sensor and the second sensor, electricity by the Seebeck effect; cooling the electronic component by the Peltier effect, using the electricity generated by the Seebeck effect.
 2. The method according to claim 1, comprising storing electrical energy, generated by the Seebeck effect, in a module capable of storing electrical energy, the stored electrical energy being used to cool the electronic component by the Peltier effect.
 3. The method according to claim 1, wherein the temperature gradient present between the first zone and the second zone of the turbojet engine is an axial temperature gradient.
 4. The method according to claim 3, wherein the first zone is a zone comprising a turbine of the turbojet engine, and wherein the second zone is a zone comprising a compressor of the turbojet engine.
 5. The method according to claim 1, wherein the temperature gradient present between the first zone and the second zone of the turbojet engine is a vertical temperature gradient.
 6. A method for cooling an electronic component in an aircraft engine, the method comprising: generating, using a first sensor and a second sensor, electricity by the Seebeck effect, the first sensor arranged in a first zone of the aircraft engine and the second sensor arranged in a second zone of the aircraft engine, the first zone and the second zone having a temperature gradient between them; and cooling the electronic component by the Peltier effect, using the electricity generated by the Seebeck effect.
 7. The method according to claim 6, comprising storing electrical energy, generated by the Seebeck effect, in a module capable of storing electrical energy, the stored electrical energy being used to cool the electronic component by the Peltier effect.
 8. The method according to claim 6, wherein the aircraft engine is a turbojet engine.
 9. A cooling system for cooling an electronic component in an aircraft engine, the cooling system comprising: a first sensor arranged in a first zone of the aircraft engine; a second sensor arranged in a second zone of the aircraft engine, the first zone and the second zone being spaced apart from each other so that a temperature gradient exists between the first and the second zone during use of the aircraft engine; a module connected to each of said first and second sensors, said module adapted to store electricity generated by the Seebeck effect resulting from the temperature gradient between the first and second zones; and a Peltier cell connected to said module and arranged to cool said electronic component using electricity stored in said module.
 10. The cooling system according to claim 8, wherein the first and second zones are located along a longitudinal axis of said aircraft engine.
 11. The cooling system according to claim 8, wherein the first and second zones are transverse to a longitudinal axis of said aircraft engine,
 12. An aircraft engine comprising: a cooling system configured to cool an electronic component in said aircraft engine, the cooling system comprising a first sensor arranged in a first zone of the aircraft engine; a second sensor arranged in a second zone of the aircraft engine, the first zone and the second zone being spaced apart from each other so that a temperature gradient exists between the first and the second zone during use of the aircraft engine; a module connected to each of said first and second sensors, said module adapted to store electricity generated by the Seebeck effect resulting from the temperature gradient between the first and second zones; and a Peltier cell connected to said module and arranged to cool said electronic component using electricity stored in said module.
 13. The aircraft engine according to claim 12, wherein the first and second zones are located along a longitudinal axis of said aircraft engine.
 14. The aircraft engine according to claim 12, wherein the first and second zones are transverse to a longitudinal axis of said aircraft engine. 